The present invention disclosed herein relates to a user device, and more particularly, to a user device including an auxiliary power supply.
User devices include electronic devices such as personal computers, digital cameras, camcorders, mobile phones, MP3s, PMPs, and PDAs, and storage devices such as memory cards, USB memories, and Solid State Drives (SSD). Most user devices include memory devices for storing data. A high capacity storage device such as a flash memory card or a solid state disk (SSD) has a typical structure including a plurality of memory devices. In general, the SSD is designed to replace a hard disk drive, and therefore, has a significantly larger capacity than a memory card. For example, the SSD may have one or two orders of magnitude greater storage space. Accordingly, the SSD includes many more memory devices than a memory card. Memory devices include volatile memories such as DRAM and SRAM, and non-volatile memories such as EEPROM, FRAM, PRAM, MRAM, and flash memory. Volatile memories lose stored data when supply of power is disrupted. However, non-volatile memories retain data when supply of power is disrupted.
User devices receive power from an internal or external power supply. Here, the power supply may be a household power supply such as 110V or 220V, an industrial power supply, or may be a charger built in the user device. The user device may suffer data loss or other serious damage due to a Sudden Power Off (SPO) of its power supply.